most of the fighting is focused on the two big cities, aleppo and damascus. but as of now, they haven't been able to take either one of them. david? >> richard engel, thank you very much. for more on this developing story, i want to go to "the atlantic's" jeffrey goldberg, also a columnist for bloomberg view, and white house correspondent for "the new york times," helene cooper. welcome to both of you. jeffrey, you covered this region extensively and have for years. you heard what the president has said and what richard has said. why this red line? something the united states never did in iraq, for instance, when hussein used chemical weapons, but we're doing it here. big shift maybe? >> well, only if you believe that it's really a red line. syrian opposition is probably correct to doubt whether the administration would do something if they use chemical weapons on their people. after all, they have been killing thousands of people every month, the assad government, using regular old conventional weapons. so it's not entirely clear to me that this would trigge